爆炸致家兔急性肺损伤及乌司他丁的保护作用

Blast-induced acute lung injury in rabbits and the protective effect of ulinastatin

目的观察爆炸致家兔急性肺损伤（ALI）时肺组织中NF-κB的表达变化，以及乌司他丁（UTI）对ALl的作用及其机制。方法建立爆炸致家兔ALI动物模型，家兔40只，随机分成五组：正常对照组（A），爆炸致伤组（B），爆炸致伤和UTI低、中、高剂量治疗组（c、D、E），每组8只。爆炸致伤1h时，C、D、E组分别注射（2．5×104,5×104、10×104U／kg）UTI溶液，A、B两组注射等量生理盐水。爆炸24h后采集肺组织及血液，并测定肺湿干质量比（W／D），蛋白印迹法测定肺组织NF-κB蛋白表达量，RT—PCR方法测定肺组织NF-κBmRNA的表达水平，ELISA法测定TNF-α、IL-6，光镜下观察肺HE切片病理变化。结果B组肺组织W／D、IL-6、TNF-α、NF-κB蛋白和NF-κBmRNA的表达量较A组显著升高（P〈0．05），C、D、E组的指标均较B组降低（p〈0．05），且E组较C、D组变化更明显；病理切片显示，B组出现严重肺组织出血、水肿以及炎细胞浸润等，而D、E组损伤较B组明显减轻。结论UTI可通过抑制NF-κB的活化，下调IL-6、TNF-α的生成，抑制炎性介质的产生，减轻肺部的损伤，这可能是其治疗ALI的机制之一。UTI可能成为治疗ALI的潜在用药之一。

Objective To investigate the changes of NF-κB in the lung tissues of rabbits with blast-induced acute lung injury （ALI）, and study the protective mechanism of ulinastatin （UTI）. Methods The model of ALl in rabbits was induced by blast. All the rabbits were randomly divided into 5 groups： control group （A）, blast- induced ALl group （B） and UTI treatment groups of different doses （C, D, E）. One hour later after blast, the rabbits in group （C, D, E） were intravenously injected with different doses of UTI （2.5×104,5×104、10×104U/kg）, while the rabbits in group A and group B were inject- ed with same volume of normal saline. The lung tissues and blood were saved at 24 hours. The NF-κB protein was evaluated by Western blotting, and the NF-κB mRNA was measured by the reverse tran- scription-polymerase chain reaction. The wet to dry weight ratios were determined; TNF-α, IL-6 were determined by ELISA method. The pathological changes of lung tissues were observed under the micro- scope. Results The levels of lung wet to dry weight ratio, NF-κB, TNF-α, IL-6 in group B were sig- nificantly higher than those in group A （P 〈 0.05）. With the treatment of UTI, the values of wet to dry weight ratio, TNF-α, IL-6, NF-κB protein and mRNA in group （C, D, E） were lower than their mea- sures in group B, and group E was the most significant group （P 〈 0.05）. Histopathology of lung tissue indicated that pulmonary hemorrhage, edema and inflammation in group （D, E） were better than that in group B. Conclusion UTI efficiently down regulates TNF-α and IL-6 expression in blast-induced ALI by inhibiting the activation of NF-κB, which may be one of its antiinflammatory actions.